Novel Hybrid Electrode Coatings Based on Conjugated Polyacid Ternary Nanocomposites for Supercapacitor Applications

Electrochemical behavior of novel electrode materials based on polydiphenylamine-2-carboxylic acid (PDPAC) binary and ternary nanocomposite coatings was studied for the first time. Nanocomposite materials were obtained in acidic or alkaline media using oxidative polymerization of diphenylamine-2-carboxylic acid (DPAC) in the presence of activated IR-pyrolyzed polyacrylonitrile (IR-PAN-a) only or IR-PAN-a and single-walled carbon nanotubes (SWCNT). Hybrid electrodes are electroactive layers of stable suspensions of IR-PAN-a/PDPAC and IR-PAN-a/SWCNT/PDPAC nanocomposites in formic acid (FA) formed on the flexible strips of anodized graphite foil (AGF). Specific capacitances of electrodes depend on the method for the production of electroactive coatings. Electrodes specific surface capacitances C_s reach 0.129 and 0.161 F∙cm^-2 for AGF/IR-PAN-a/PDPAC_ac and AGF/IR-PAN-a/SWCNT/PDPAC_ac, while for AGF/IR-PAN-a/PDPAC_alk and AGF/IR-PAN-a/SWCNT/PDPAC_alk C_s amount to 0.135 and 0.151 F∙cm^-2. Specific weight capacitances C_w of electrodes with ternary coatings reach 394, 283, 180 F∙g^-1 (AGF/IR-PAN-a/SWCNT/PDPAC_ac) and 361, 239, 142 F∙g^-1 (AGF/IR-PAN-a/SWCNT/PDPAC_alk) at 0.5, 1.5, 3.0 mA·cm^-2 in an aprotic electrolyte. Such hybrid electrodes with electroactive nanocomposite coatings are promising as a cathode material for SCs.